基于消光法反演单分散Au-Ag合金纳米球的粒径和浓度

Particle Size and Concentration of Monodisperse Au-Ag Alloy Nanospheres Retrieved by Light Extinction Method

基于Mie理论分析单分散Au-Ag合金纳米球消光特性随粒径和波长的变化情况。在理论计算中,根据金属纳米颗粒中自由电子平均自由程的缩短效应对Au-Ag合金纳米颗粒的介电函数进行修正。基于消光特性提出了三种确定粒径和浓度的拟合公式,包括共振波长法、双波长消光法和改进的双波长消光法。结果表明,只要测得颗粒的消光谱,就能利用拟合公式反演颗粒的粒径和浓度。此外,对比三种方法的灵敏度和粒径范围发现,相比其他方法,共振波长法的原理更简单、速度更快。

Variation of light extinction properties of monodisperse Au-Ag alloy nanospheres with particle size and wavelength are analyzed based on Mie theory.In the theoretical calculations,the dielectric function of Au-Ag alloy nanoparticles is corrected for the effect of the reduced mean free path of the free electrons in metal nanoparticles.Three fitting equations for determining particle size and concentration methods based on the extinction properties are proposed in this paper,including resonance wavelength method,dual-wavelength extinction method,and improved dual-wavelength extinction method.The results show that as long as the extinction spectrum of the particles is measured,the particle size and concentration can be retrieved by using the fitting equations.In addition,comparing the sensitivity and the particle size range of three methods are found that the resonance wavelength method is easier and faster than other methods.